This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. PACTG P1047 is a safety and immunogenicity pilot study of quadrivalent HPV vaccine (QHPV Vaccine) in HIV-infected children. This study represents the initial step in evaluating a prophylactic vaccine, which might protect HIV-infected girls and boys from infection with the most common HPV types that cause anogenital dysplasia and external genital lesions. The long-term goal, following successful completion of this study, is to undertake an efficacy trial in HIV-infected children using QHPV Vaccine, in order to prevent infection and disease caused by the HPV types contained in the vaccine. It is likely that a follow-up efficacy trial will rely heavily on international sites. This protocol will be undertaken in children >7 to <12 years of age because it is likely that this preventative vaccine will be used before children become sexually active. It is expected that, in terms of safety, QHPV Vaccine will be generally well-tolerated in HIV-infected children >7 to <12 years of age. In terms of immunogenicity, administration of a 3-dose regimen of QHPV Vaccine is expected to be immunogenic in at least one immune stratum of HIV-infected children >7 to <12 years of age. QHPV Vaccine will be generally well-tolerated in HIV-infected children >7 to <12 years of age. Administration of a 3-dose regimen of QHPV Vaccine will be immunogenic in at least one immune stratum of HIV-infected children >7 to <12 years of age. It is anticipated that the true proportion of HIV-infected subjects who will seroconvert for each vaccine HPV type will be at least 80% in one immune strata. Seroconversion is defined as the development of antibody levels above the established seropositivity cutoff for each HPV type at Week 4 post-administration of the third dose, in subjects who were na[unreadable][unreadable]ve at baseline to the relevant HPV type. Subjects were considered na[unreadable][unreadable]ve if their baseline antibody level was less than the seroconversion cutoff. Sero-cutoff values will be established for each HPV type based on a qualification plan examining known HPV-negative and low positive sera. The statistical criterion for success requires that the lower bound of 95% CI for the proportion of subjects who seroconvert be greater than 50%. 1. To determine the safety and tolerability of QHPV Vaccine in HIV-infected children ages >7 to <12 years. 2. To determine seroconversion after vaccination with QHPV Vaccine in HIV-infected children ages >7 to <12 years.